A fort was established in the site of Sunchales on 11 April 1796 to prevent attacks by aboriginal tribes and guard the road used to carry mercury from Buenos Aires to be at the mines in present-day Peru. The fort also guarded a settlement of about 1,000 people. In 1810, on the wake of the May Revolution, a number of the stationed soldiers were recruited for the independents expedition led by Manuel Belgrano to Paraguay. The settlement was disbanded by an aboriginal incursion.
In 1867, under the provincial government of Nicasio Oroño, colonists came into the area from Esperanza. The fort was again depopulated when its forces were sent to combat the aboriginal tribes in the north of the province and the south of Chaco, and the colonists disbanded. A few years later, sponsored by governor Mariano Cabal, a group of immigrants (Italian, French, Swiss, German, Spanish, British and Belgian) came into the area, but bad harvests, food shortages and native attacks caused the settlement to fail once again.
The last attempt was conducted by Carlos Christiani, with the first immigrants arriving in 1884. The land plan of the new colony was approved by governor José Gálvez on October 19, 1886. The town was declared a city on the 81st anniversary of its official foundation, in 1967
